In a transmission/reception device of an information processing system, a transmission system for data transmission between the transmission/reception ports obtained by a plurality of bound serial interfaces connected in a point to point system is adopted. A serial interface connected in a point to point system can typically be, for example, a PCI (Peripheral Component Interconnect)-Express. The connection line between the ports in serial interfaces is generally called a lane.
In a method of a connection test between printed circuit chips, it is proposed to provide a device for assigning a test pattern to an output pin of a chip of a connection line in a printed circuit, acquiring a test value from an input pin of the chip of the connection line, and comparing the value with an expected value.
In an inter-LSI (Large Scale Integrated circuit) connection test circuit, it is proposed to provide a comparison device for comparing test data from a test data storage device with the contents of the test data returned by a signal communication device for returning test data through an external integrated circuit.
Furthermore, in an LSI having a connection test function, it is proposed in a connection test of an LSI chip to provide an input/output selection circuit capable of switching an input signal input from one input terminal to a plurality of output terminals, and input signals from a plurality of input terminals to a plurality of output terminals.
Furthermore proposed in a method of specifying a faulty lane and switching the capacity of the width of two CSI (Common System Interface) agent connected through a link is a method of transmitting and receiving the information about a link width between first and second agents and adjusting a link width.    Patent Document 1: Japanese Laid-open Patent Publication No. 2-245675    Patent Document 2: Japanese Laid-open Patent Publication No. 5-53857    Patent Document 3: Japanese Laid-open Patent Publication No. 2004-205352    Patent Document 4: Japanese Laid-open Patent Publication No. 2005-332357